That confirms *exactly* (especially the ASN integers) what I am seeing. I am able to move forward now with this info. Thank you for the help.



Quoting Jeffrey Walton <noloa...@gmail.com>:

Hi Mark,

I think I need to pull some data out of the header in the openssl DER file
and put it into the key BLOB (BLOBHEADER/RSAPUBKEY) structure in Windows.
When you pluck the various ASN Integers out of the DER encoded key
file, the integers have to be baked a bit before inserting into the
BLOB. For some reason, Microsoft uses little endian format on some of
the byte arrays in the BLOB (while ASN Integer's byte array ('content
octets') are big endian).

I also seem to recall issues when providing a byte array from an ASN
integer: ASN integers are two's compliment, so a 0x00 octet is
prepended to the content octets if the high bit if octet[0] is set to
ensure the data is positive. But some Microsoft component did not like
it - the prepended octect caused the length of the array to change
from 128 bytes to 129 bytes.

Jeff

On Fri, Jul 2, 2010 at 10:51 AM, Mark Bishop <m...@bish.net> wrote:
I am trying to take a DER formatted public key and putting the key into the
Window's Crypt library so that my Windows machine can send my linux machine
encrypted data.

Trying to compile openssl for Windows is not on the table right now.  I am
being forced to use the Windows Crypt library.

Does anyone have some information that might be able to get me on my way?  I
am not a security (openssl) specialist, but I am learning rapidly.

I think I need to pull some data out of the header in the openssl DER file
and put it into the key BLOB (BLOBHEADER/RSAPUBKEY) structure in Windows.

Right now, when I encrypt the same data on Windows and Linux, the Windows
one is 148 bytes and the Linux one is 128 bytes - the input data file is 16
bytes.  I am doing something very wrong.

If there is any hope for me, please let me know.
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______________________________________________________________________
OpenSSL Project                                 http://www.openssl.org
User Support Mailing List                    openssl-users@openssl.org
Automated List Manager                           majord...@openssl.org

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